Embargoed news from Annals of Internal Medicine

(Press-News.org) 1. A Low-carb Diet Based on Animal Protein May Increase Death Risk

Evidence shows that a low-carbohydrate diet produces weight loss and improves some cardiovascular risk factors. However, health effects of a low-carbohydrate diet may depend on the type of protein and fat consumed. Researchers followed 85,168 women and 44,548 men on a low-carbohydrate diet for 26 and 20 years respectively. The patients ate either an animal-based (emphasizing animal sources of fat and protein) low-carbohydrate diet, or a vegetable-based low-carbohydrate diet. The researchers found that diets that emphasized animal sources of fat and protein were associated with higher all-cause mortality in both men and women. A vegetable-based low-carbohydrate diet was associated with lower all-cause and cardiovascular disease mortality rates. The researchers conclude that while major macronutrient content may be similar in both diets, the source of the macronutrients can result in large differences in dietary components that may affect mortality such as specific fatty acids, protein, fiber, vitamins and minerals, and phytochemicals.

2. Patients Overestimate the Benefits of Percutaneous Coronary Intervention (Angioplasty)

Compared with medical therapy, percutaneous coronary intervention, or PCI (commonly known as angioplasty) reduces angina symptoms, but does not reduce risk of myocardial infarction or death. However, it is not known whether patients understand the limits of what PCI procedures can offer. Researchers surveyed 153 patients who consented to elective cardiac catheterization with PCI if indicated by catheterization results and 27 cardiologists about the expected benefits of the procedure. Cardiologists' beliefs paralleled the available evidence. Conversely, most patients thought that PCI would prevent infarction or death. The researchers conclude that physicians and patients may need to discuss anticipated benefits prior to PCI to provide a clearer understanding of what these types of procedures can and cannot do.

3. Radiation-free MRA Provides Accurate Diagnosis of Peripheral Arterial Disease in the Lower Extremities

Lower extremity peripheral arterial disease, or PAD, affects about 10 percent of adults older than 60. An accurate diagnosis is important because PAD increases risk for coronary artery disease, heart attack, stroke, and mini stroke. However, common diagnostic tests such as CTA and DSA are radiation-based. Researchers sought to determine how well radiation-free contrast-enhanced magnetic resonance angiography (MRA) identifies or excludes arterial steno-occlusions in adults with PAD symptoms. The researchers reviewed 32 studies that compared MRA with intra-arterial digital subtraction angiography. They found that contrast-enhanced MRA has both a high sensitivity (about 94.7 percent) for identifying and a high specificity (about 95.6 percent) for excluding arterial steno-occlusions in adults with PAD symptoms. The researchers conclude that MRA is an important diagnostic alternative to CTA and DSA.

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